Determination of 2-Propanol Residue in Some Fruits Dewaxed with Alcohol Vapors

Abstract A quantitative method is described for the determination of 2-propanol in apples and grapes exposed to alcohol vapors. This method was also applied to eggplants. The procedure includes the following: homogenizing the product in a blender and filtering the slurry; weighing an aliquot of the filtrate into a serum bottle containing 1-propanol, the internal standard; equilibrating the liquid and gas phases; sampling the headspace vapor and analyzing by gas-solid chromatography (GSC). A time-temperature study using model alcohol systems indicated that equilibration at 65 °C for 60 min gave the most constant peak area ratios of 2- propanol: 1-propanol as measured by GSC. The peak area ratio was directly proportional to the concentration of 2-propanol over the range 0舓180 ppm. The recovery of 2-propanol added to untreated apple juice was excellent within this range.